In offshore drilling and production operations, equipment is often subjected to harsh conditions thousands of feet under the sea surface with working temperatures of −50° F. to 350° F. with pressures of up to 15,000 psi. Subsea control and monitoring equipment commonly are used in connection with operations concerning the flow of fluid, typically oil or gas, out of a well. Flow lines are connected between subsea wells and production facilities, such as a floating platform or a storage ship or barge. Subsea equipment includes sensors and monitoring devices (such as pressure, temperature, corrosion, erosion, sand detection, flow rate, flow composition, valve and choke position feedback), and additional connection points for devices such as down hole pressure and temperature transducers. A typical control system monitors, measures, and responds based on sensor inputs and outputs control signals to control subsea devices. For example, a control system attached to a subsea tree controls down-hole safety valves. Functional and operational requirements of subsea equipment have become increasingly complex along with the sensing and monitoring equipment and control systems used to insure proper operation.
To connect the numerous and various sensing, monitoring and control equipment necessary to operate subsea equipment, harsh-environment connectors are used with electrical cables, optical fiber cables, or hybrid electro-optical cables. Initial demand for subsea connector development was in connection with military applications. Over time demand for such connectors has grown in connection with offshore oil industry applications.
Early underwater connectors were electrical “dry-mate” devices, intended to be mated prior to immersion in the sea and were of two principal types: rubber-molded “interference fit” type and rigid-shell connectors. The rubber molded “interference-fit” connectors depended on receptacles with elastic bores that stretched and sealed over mating plugs. The rigid-shell connectors had mating parts sealed together via O-rings or other annular seals.
However, there was a demand for connectors that could also be mated in the subsea environment. These so called “wet-mate” connectors were adaptations of the interference-fit dry-mate versions, and were designed so that when mated, the water contained in the receptacle bores would be substantially expelled prior to sealing. Additionally, oil-filled and pressure-balanced electrical connector designs were introduced which isolated the receptacle contacts within sealed oil-chambers which, during engagement, were penetrated by elongated pins with insulated shafts. Connection was, therefore, accomplished in the benign oil, not in harsh seawater. The oil-filled connectors provide one or more seals that allow the oil chambers to be penetrated repeatedly without losing the oil or allowing seawater intrusion.
There are many types of connectors for making electrical and fiber-optic cable connections in hostile or harsh environments, such as undersea or submersible connectors which can be repeatedly mated and de-mated underwater at great ocean depths. Current underwater connectors typically comprise releaseably mateable plug and receptacle units, each containing one or more electrical or optical contacts or junctions for engagement with the junctions in the other unit when the two units are mated together. Each of the plug and receptacle units or connector parts is attached to cables, which may be referred to as flying leads, or other devices intended to be joined by the connectors to form completed circuits. To completely isolate the contacts to be joined from the ambient environment, one or both halves of these connectors house the contacts in oil-filled, pressure-balanced chambers—this is referred to as a pressure balanced set-up. Such devices are often referred to as “wet-mate” devices and often are at such great depths that temperature and other environmental factors present extreme conditions for materials used in such devices. The contacts on one side (plug) are in the form of pins or probes, while the contacts or junctions on the other side (receptacle) are in the form of sockets for receiving the probes. Examples of prior dry-mate, wet-mate, and pressure compensated wet-mate connector systems that have been used in subsea environments are described in U.S. Pat. Nos. 4,616,900; 4,682,848; 4,666,242; 4,795,359; 5,194,012; 5,685,727; 5,738,535; 5,838,857; 6,315,461; 6,736,545; and U.S. Pat. No. 7,695,301, each of which is incorporated herein in its entirety.
In these prior art connection systems, either the plug and receptacle components of the connection system must be mated on the surface in the case of the dry-mate connection systems or in the subsea environment in the case of wet-mate connection systems. For wet-mate connection systems, the connections may be mateable by a diver if the connection is at a shallow enough depth that it can be reached by a diver using suitable equipment. For connections at greater depths or connections in more hazardous conditions, a remote operated vehicle (“ROV”) is typically used. Many types of ROVs exist, but most that are employed in the subsea oil and gas extraction industry typically have one or more robotic manipulators. These manipulators are typically not very complex, and may only comprise a vise-like or pliers-like gripper or manipulator only having two digits, of which only one may be movable. More advanced robotic manipulators exist, however, even these may not be able to properly operate overly complicated connection systems in subsea conditions where temperature, fluid turbulence, or low visibility may impair operation.
To this end, typical connection systems usually feature a robotically manipulatable component on the plug unit part of the connection system. For example, the plug unit in the connection system described in U.S. Pat. App. 2014/0270645 entitled COMPOSITE CONNECTION SYSTEM, to Toth, which is incorporated by reference herein in its entirety, provides a plug unit having a robotically manipulatable handle disposed at the rear of the plug unit. The handle in Toth is a fixed assembly that is not removable from the plug unit and is fastened, semi-permanently, to the plug unit. This means that each plug unit used in the system in Toth, like most prior art systems, must have its own robotically manipulatable handle.
In systems like the one described in Toth, the flying connection unit must be designed and constructed to withstand forces exerted on the flying connection unit by manipulation of the handle during mating and de-mating procedures. For example, when the flying connection unit is being mated with the receptacle unit, axial and radial forces may be applied to the housing or shell of the flying connection unit that could fracture the flying connection unit, compromising the pressure integrity of the flying connection unit itself. This type of pressure integrity loss would render the flying connection unit unusable and would require a complete replacement of the flying connection unit which would necessitate bringing the flying connection unit to the surface for repairs. Such a repair would be costly and time consuming. Furthermore, in order to design the flying connection unit to withstand the forces of mating and de-mating exerted on the plug unit by the handle, the flying connection must be designed to be robust and strain or stress resistant. This design increases the cost of the flying connection unit because of the type and amount of material that must be used to make the flying connection unit sufficiently robust. For example, the flying connection unit would need to be made of a suitable metal that could withstand the strain of mating and de-mating exerted on the flying connection unit housing by the attached handle. Moreover, providing each flying connection unit with its own handle significantly increases the cost and complexity of each flying connection unit.
What is needed is an improved flying lead connection system having a removable robotically manipulatable tool that provides for greater flexibility, is robust and less subject to breakage resulting from plug manipulation and has a reduced cost and complexity for each plug unit in the connection system.